Pear tree problem

A lady whose garden I do voluntary work for has a pear tree which has what looks like some kind of infection. I don't know what it is but I've included a picture - any ideas what it could be? Its the little browny-grey squidgy things on the underside of leaves - very unscientific I know

 

Looks like Pear rust. No cure for the amateur, but not really a major problem in the UK most years. Recommend removing any damaged leaves and disposing of them, same for any which fall too.

 

Yep, that's it I think, I'll let the lady know. Thanks very much, really appreciate it

 

our 2 trees have it as well , no fruit really either this year but im blaming the weather